title: Networks involved in olfaction and their dynamics using independent component analysis and unified structural equation modeling.
abstract: The study of human olfaction is complicated by the myriad of processing demands in conscious perceptual and emotional experiences of odors. Combining functional magnetic resonance imaging with convergent multivariate network analyses, we examined the spatiotemporal behavior of olfactory-generated blood-oxygenated-level-dependent signal in healthy adults. The experimental functional magnetic resonance imaging (fMRI) paradigm was found to offset the limitations of olfactory habituation effects and permitted the identification of five functional networks. Analysis delineated separable neuronal circuits that were spatially centered in the primary olfactory cortex, striatum, dorsolateral prefrontal cortex, rostral prefrontal cortex/anterior cingulate, and parietal-occipital junction. We hypothesize that these functional networks subserve primary perceptual, affective/motivational, and higher order olfactory-related cognitive processes. Results provided direct evidence for the existence of parallel networks with top-down modulation for olfactory processing and clearly distinguished brain activations that were sniffing-related versus odor-related. A comprehensive neurocognitive model for olfaction is presented that may be applied to broader translational studies of olfactory function, aging, and neurological disease.
authors.affiliation: Department of Radiology (Center for NMR Research), The Pennsylvania State University College of Medicine, Hershey, Pennsylvania.
authors.forename: Prasanna
authors.initials: P
authors.lastname: Karunanayaka
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Eslinger
authors.forename: Jian-Li
authors.initials: JL
authors.lastname: Wang
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Weitekamp
authors.forename: Sarah
authors.initials: S
authors.lastname: Molitoris
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Gates
authors.forename: Peter C M
authors.initials: PC
authors.lastname: Molenaar
authors.forename: Qing X
authors.initials: QX
authors.lastname: Yang
mesh_terms: D000328:Adult; D001921:Brain / Q000098:blood supply* / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D009812:Odorants; D009833:Olfactory Pathways / Q000098:blood supply*; D010100:Oxygen / Q000097:blood; D025341:Principal Component Analysis; D011601:Psychophysics; D012903:Smell / Q000502:physiology*; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: fMRI; independent component analysis; olfaction; structural equation modeling